Feynman had the vanishingly rare combination of being at world-shaking (literally) historical events like the Manhattan Project and the Trinity test that ordinary people can relate to¹, actual scientific contribution enough to merit a Nobel Prize in Physics, and being an engaging storyteller and educator. I don't think it's all that surprising that his recognizability very high.

¹ Ordinary people can relate to a giant industrial project and a huge boom. They cannot relate to some person sitting in a room writing arcane symbols and muttering to themselves until one day they yell "Heureka! Ich hab es gefunden!" or whatever the proper German is and rush off to publish a paper.

My point is that it's really the storytelling/gregarious nature character. There is no shortage of people who were at the Manhattan project and won Nobel prizes or were prominent. A partial list: Oppenheimer, Bethe, Rabi, Teller, von Neumann, Compton, Fermi, Segre, Ramsey, Alvarez. There are easily many more. Schwinger was at Rad lab.

Schwinger was considered a tremendous educator. I think he had ~90 PhD students and four won Nobel prizes. His lectures were often described as Mozart symphonies. I have studied parts of his books and the experience was always eye-opening. But, his education was focused on students, mostly graduate students. He was also a shy character.

In any case, I still love reading Feynman and Schwinger's works. I would also include Sommerfeld, Pauli, Landau, Weinberg in that list.